Study of saliva microbes reveals similarities across the globe

The microbial life inhabiting the mouth of the person next door is likely to be just as different from yours as that of a person on the other side of the world, according to an article in the journal Genome Research.

Researchers from the Max Planck Institute for Evolutionary Anthropology, Shanghai Institutes for Biological Sciences, and China Pharmaceutical University analyzed saliva samples in 120 healthy subjects from 12 locations around the world. They then compared the samples with those in a database to categorize the types of bacteria present.

The researchers observed that there is considerable diversity of bacterial life in the saliva microbiome — the world of microbes, their genomes and their environmental interactions in a defined environment such as an individual's saliva — within and between people. They made an unexpected finding, however, when they compared samples from different geographic areas.

"The saliva microbiome does not vary substantially around the world, which seems surprising given the large diversity in diet and other cultural factors that could influence the human salivary microbiome," said author Mark Stoneking, PhD, of the Max Planck Institute.

Dr. Stoneking said their work has provided the foundation for future studies exploring the influence of diet, cultural factors and disease on variation in the saliva microbiome and their findings could help in the analysis of human migrations and populations as well as oral health research.

Saliva has been the subject of research as a diagnostic fluid for oral and systemic conditions, allowing for development of new rapid and non-invasive saliva-based diagnostic tests to replace blood sample procedures in current use. Mapping the saliva microbiome is a key element in the development of saliva-based tests for cancer, heart disease, diabetes and other conditions.